From 1282, he ruled a separate kingdom which included northern Serbia, and (from 1284) the neighboring Hungarian banates (or border provinces), for which he was unofficially styled "King of Syrmia".

After a riding accident, he abdicated in favor of his brother Milutin in 1282, but retained the northern regions of Serbia along the Hungarian border.

In theory, Dragutin was a vassal both to his brother (for his Serbian territories), and to the Hungarian monarchs (for the four banates), but in practice he ruled his realm as an independent ruler from the 1290s.

[10] In 1264, the monk Domentijan recorded that the "fourth generation" of the descendants of Stefan Nemanja was already old enough "to ride a horse and carry a warrior's lance".

[6] His father and her grandfather, Béla IV of Hungary, most probably arranged the marriage during the peace negotiations that followed Uroš I's invasion of Mačva in 1268,[6][7][12][13] but an earlier date cannot be excluded.

[14][15] The peace agreement may have explicitly prescribed the division of Serbia between Uroš I and Dragutin, according to Aleksandar Krstić and other historians.

[16] Whether he wanted to persuade his father to share power with him, or he was afraid of being disinherited in favor of his younger brother, Milutin, cannot be determined.

[16] His abdication may have been to protest Dragutin's usurpation of the throne, or he may have been forced to resign because of his close relationship with the dethroned monarch.

[16] Soon after ascending the throne, Dragutin gave large parts of Serbia—including Zeta, Trebinje and other coastal territories, and Plav—to his mother in appanage.

[18] The lands of Helen's appanage included the core territories of the former Kingdom of Duklja and developed into a province of the heirs to the Serbian throne after her death.

[15] Charles I of Anjou, King of Sicily, wanted to include Dragutin in a coalition against the Byzantine Empire.

[34] Charles Martel, who regarded himself the lawful king of Hungary, granted Slavonia to Dragutin's son, Vladislav, in 1292,[34] but most Hungarian noblemen and prelates remained loyal to Andrew III.

[35] Dragutin took advantage of the disintegration of Hungary during the last decade of the 13th century and became one of the dozen "oligarchs" (or powerful lords) who ruled vast territories independently of the monarch.

[26] After Milutin had made peace with the Byzantine Empire in 1299, dozens of Serbian noblemen, who had benefited from the war, moved to Dragutin's realm.

[40] According to Ragusan reports, a peace treaty was made in late 1302, but Dragutin's troops or allies pillaged Milutin's silver mines at Brskovo in 1303.

[40][41] The parties allegedly avoided fighting pitched battles and Dragutin kept his realm almost intact, although income from the silver mines enabled Milutin to hire mercenaries.

His ally John Smaragd led Dragutin's army, but was defeated by Paul Garai, Ugrin's commander.

[47] Dragutin also seized properties of the Archbishopric of Kalocsa, which prevented the newly elected Archbishop Demetrius from visiting Rome before the end of 1312.

[39][46] The Serbian prelates remained loyal to Milutin and helped him to hire Tatar, Jassic and Turkish mercenaries.

[49] Dragutin had to acknowledge his brother as the lawful king, but his Serbian appanage (including the silver mine at Rubnik) was fully restored to him.

[50][51] Dragutin sent reinforcements to help his brother's fight against the powerful Ban of Croatia, Mladen II Šubić of Bribir, in 1313.